Disruptive MRF Technology

The sorting of commingled recyclables traditionally uses a “presort station” where non-program material can be removed prior to entering the sorting facility. Because this sort station is at the entrance to the facility this is done without any benefit of automation or separation, making the process dangerous, inefficient and labor intensive.

Due to changes in the material stream over the last decade reducing inbound material density and persistent labor shortages in the industry, presorting is more problematic than ever. Staffing a MRF to properly presort an inbound stream is almost impossible in certain markets, decreasing throughput and increasing downtime. When a MRF is able to staff properly for the challenges, it results in increased operating costs to achieve the same results of a decade earlier.

The presort station is not a candidate for automation due to large burden depth and a large degree of material variability, so as the industry moves toward fully automated recycling, the solution is not to automate the presort but to eliminate the presort by developing machines which do not suffer downtime or damage as a result of non-program material. The only reason to have a presort is to protect machines. Machines which don’t need protection would therefore not need a presort.

The use of Auger Screens in American recycling was a first step toward eliminating the presort. The use of a Primary Auger Screen reduced material burden at the presort by up to 60% and reduced presort labor by up to 50%. This is especially important in high residue markets which typically use a lot of pre-sorters. However, primary auger screens could not produce a finished product; positive sorting of non-program material still was still necessary before final product screening and sorting, and so a fully automated MRF was still out of reach. This is due to an inherent issue in the screws used to create an auger screen – they are round, and round shafts don’t produce enough material agitation to create final products such as OCC. The lack of agitation inherent in the screen made “surfing” inevitable, and so attempts to use auger screens as OCC screens resulted in too much fines contamination, such as glass, to either QC or sell to market. A new innovation was needed.

Recognizing the need for a non-wrapping, non-jamming, finished product screen in order to fully automate a MRF, CP Manufacturing began investigating solutions in 2016. One of the first avenues of investigation was the use on non-round screws in the auger screen. This would provide the proven agitation of a disc screen in a format suitable for a fully automated MRF.

A non-round screw combines the dynamics of discs with the continuous nature of a screw flight in a way that presents a novel, bidirectional clocking challenge. However, CP Manufacturing overcame these design challenges in late 2017. These innovations resulted in two U.S. Patents.

With a prototype designed, the next challenge involved manufacturing of the shapes and flights necessary to make a clocked, non-jamming and non-round Auger Screen. In 2019 we completed this manufacturing investigations process and created the first prototype machine.

CP installed this machine at their MRF in San Diego in June, 2020 for commercial and performance testing and demonstration. Small tweaks were made to the machine design but overall the test was a resounding success – the machine produced finished grade OCC at a throughput equal to traditional OCC screens without any wrapping or jamming.

There are currently two OCC Auger Screens in operation on commercial material, including the original prototype, as well as one high-volume single stream Landmark MRF.

Several additional MRFs using the OCC Auger Screen are currently in production for startup over the next three years. High volume residential single stream MRFs which have zero manual sorters are currently in the quoting stage. Such a MRF is not possible without the innovation of a high-agitation auger screen.

The CP Auger Screens have disrupted American MRF process flows. The disruption is welcomed and necessary. It is truly the first of its kind innovation that lends itself to the next phase in MRF process evolution and automation. It is the catalyst to the MRF of the Future by eliminating the presort and enabling more automation.

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